<!DOCTYPE html>
<html>
<head>
  <style>
    .flexContainer {
      display: flex;

      /* Just for easier visualization: */
      width: 600px;
      justify-content: space-around;
      border: 1px solid black;
    }

    .flexContainer:before {
      position:absolute;
      content:'before';
    }
    .flexContainer:after {
      position:absolute;
      content:'after'
    }

    .ordered-item {
      position:relative;
      order:5;
    }
    </style>
  </head>
  <body>
    <div class="flexContainer">
      <div class="ordered-item">ItemWithOrderSet
        <!-- It's important that this remain unclosed, for some reason. -->
